In case of contumacy by, or refusal to obey a subpena issued to, any person, the Secretary of the Treasury may invoke the aid of any court of the United States within the jurisdiction of which the investigation is carried on or of which the subpenaed person is an inhabitant, carries on business or may be found, to compel compliance with the subpena of the Secretary of the Treasury. The court may issue an order requiring the subpenaed person to appear before the Secretary of the Treasury there to produce records, if so ordered, or to give testimony touching the matter under investigation. Any failure to obey the order of the court may be punished by the court as a contempt thereof. All process in any such case may be served in the judicial district whereof the subpenaed person is an inhabitant or wherever he may be found.